Stackable chair with foldable tablet arm

ABSTRACT

A stackable and gangable chair having a folding tablet arm movable between a horizontal position disposed directly above a portion of the chair seat and a downwardly and outwardly sloping position located sidewardly of said seat. The tablet arm is mounted upon upwardly diverging support elements connected to legs on one side of said seat. The legs, which are rigidly secured to the seat, have front and rear pairs which diverge downwardly. Ganging members are rigidly connected either directly or indirectly to the legs on both sides of the seat. The ganging members and the support elements are arranged so that one of said chairs can be nested on top of another of said chairs when their tablet arms are in their outwardly and downwardly sloping positions.

United States Fink Patent 1 STACKABLE CHAIR WITH FOLDABLE TABLET ARM Inventor: Roy W. Fink, Portage, Mich.

The Vecta Group, Inc., Kalamazoo, Mich;

Filed: Jan. 21, 1971 Appl. No.: 108,511

Assignee:

References Cited UNITED STATES PATENTS Piretti et a1 ..297/239 Van Ryn .;..297/l62 Blodee Orman 51 Jan.23,1973

3,610,686 10/1971 Caruso ..297/445 Primary Examiner-James T. McCall Attorney-Woodhams, Blanchard & Flynn [57] ABSTRACT A stackable and gangable chair having a folding tablet arm movable between a horizontal position disposed directly above a portion of the chair seat and a downwardly and outwardly sloping position located sidewardly of said seat. The tablet arm is mounted upon upwardly diverging support elements connected to legs on one side of said seat. The legs, which are rigidly secured to the seat, have front and rear pairs which diverge downwardly. Ganging members are rigidly connected either directly or indirectly to the legs on both sides of the seat. The ganging members and the support elements are arranged so that one of ,said chairs can be nested on top of another of said chairs when their tablet arms are in their outwardly and downwardly sloping positions.

8 Claims, 12 Drawing Figures PATENTEDJAHZCB ms 3.712.668

sumznrs yENToR P0 'F/NK ATTOPA [I PATENTEUJANZS I973 3.712.668

SHEET 3 or 3 INVENTOR Maw W STACKABLE CHAIR WITH FOLDABLE TABLET ARM FIELD OF THE INVENTION This invention relates in general to a nestable and gangable tablet arm chair and, more particularly, to a type thereof having a hinged tablet arm which is movable from a substantially horizontal operational position into a downwardly and outwardly sloping storage position which permits stacking of said chair with another similar chair.

BACKGROUND OF THE INVENTION Persons familiar with the use and manufacture of gangable and stackable chairs, and especially chairs used in schools, auditoriums and the like, where it is desirable to have a tablet arm, are aware that much work and effort have been directed to the development of a completely acceptable chair capable of meeting these requirements. However, chairs produced for this purpose to date have not fulfilled the need due to one or more reasons. That is, either the chair could not be both stacked and ganged if it had a foldable tablet or, if stackable and gangable, the tablet remained in an awkward position when in itsstorage'or stacking position. Moreover, it was found that stackable tablet armchairs having movable tablet arms had sacrificed strength to the extent that they could not be used without risk of early break-down in situations where reasonable, but

rough, treatment could be expected. I

parts at the point of connection. However, the typical weld is no better. That is, the welding creates an annealed zone with a reduced yield strength, an abrupt and material change in cross-sectional area which con centrates stress, and a stiffened section which effectively resists distribution ofa bending moment beyond the I change in cross-sectional area. Thus, it comesas no surprise that failures under stress are most likelyto.

occur at, or even be induced by, a typical weld betwee the legs and ,arm support bracket.

- Accordingly, a primary object of this invention is the provision of a stackable and gangable chair having a tablet arm capable of hinged movement between an operative position and astorage position, said storage position being such that obstruction to stacking and storage is minimized. I

A further object of this invention is the provision-ofa stackable chair which has a hinged tablet armcapable of withstanding abusive use, which is easy to maintain and is relatively simple in construction. I

A further object of this invention is the provision-ofa device for connecting a metallic tablet arm support to metallic legs of a chair whereby the annealing effects of welding are minimized, an abrupt and material change in cross-sectional area is avoided and a substantially stiff section is eliminated.

Other objects and purposes of this invention will i become apparent to persons familiar with chair structures of this type upon reading the following descriptive material and examining the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS operative position.

FIG. 4 is a sectional view taken along the line lV--lV in FIG. 3.

FIG. 5 is a fragmentary sectional view taken along the line V-V in FIG. 3.

FIG. 6 is a sectional view taken along the line VIVI in FIG. 3.

FIG. 7 is a sectional view taken along the line VII- VII in FIG. 6

FIG. 8 is a sectional view taken along the line Vlll VIII in FlG..2.

FIG. 9 is a broken fragment of FIG. 6.

FIG. l0 is a front elevational view of the pair of chairs in the stacked position.

FIG. 11 is a sectional view taken along the line XI- XI in FIG. 10.

FIG. 12 is a sectional view substantially as taken along the line XII-XII in FIG. 8.

For convenience in description, the terms upper," "lower, front, rear and words of similar import will have reference to the chair embodying the invention as appearing in FIG. 3 which illustrates front views of the chair. 7

The words right and left will have reference to those sides of said chair adjacent the right and left sides, respectively, ofa person occupying said chair in a normal manner.

SUMMARY OF THE INVENTION The objects and purposes of the invention, including those set forth above, have been met by providing a stackable and gangable chair having a folding tablet arm movable between a substantially horizontal operative position and a downwardly and outwardly sloping storage or stacking position. The tablet arm is hingedly mounted upon the upper end of a tablet support member, which in turn is rigidly secured to the legs of the chair. The tablet support member has upwardly diverging arms, and the front chair legs diverge downwardly with respect to the rear chair legs to permit stacking. Mating ganging members are mounted upon the legs on the opposite sides of the chair, which DETAILED DESCRIPTION FIGS. land 2 illustrate a chair l0 constructed according to the present invention. The chair 10 includes a back 11 and a seat 12 which, in a preferred embodiment of the invention, are constructed in one piece. The chairv 10 includesright front and rear legs 13 and I4 and additionally includes left front and rear legs 16 and 17. The pair of right legs 13 and 14 diverge downwardly away from the seat, as do the left legs 16 and 17, in order to permit stacking of two such chairs 10. The pair of legs 13 and 14 define a substantially vertical plane and they are disposed slightly outwardly of the right edge of the seat 12. The pair of legs 16 and 17 define a substantially vertical plane and they are disposed slightly outwardly of the left edge of the seat. The front legs 13 and 16 preferably define a plane which slopes downwardly and forwardly relative to the seat 12, and the rear legs 14 and 17 preferably define a plane which slopes downwardly and rearwardly relative to the seat.

The front legs 13 and 16 are rigidly connected, here integrally, to a center support portion 18 which extends primarily in the horizontal direction and which is disposed adjacent to and under the chair seat 12. The rear legs 14 and 17 are also rigidly, here integrally, connected by a center support portion 19 which is disposed adjacent to and under the seat, but rearwardly of the front center support portion 18. Suitable mounting means 21 is rigidly secured to and extends between the center support portions 18 and 19, and said mounting means 21 is rigidly connected to the chair seat 12.

The chair construction described above may be substantially conventional. Further, the downwardly diverging front and rear legs of the chair may be formed with their respective center support portions from two pieces of tubing so that they appear as a pair of U-shaped members before connection to the mounting means 21.

The chair is provided with a substantially V- shaped tablet arm support 22 which is secured to the legs 13 and 14 and opens upwardly. A tablet arm 23 is mounted upon the upper free ends of the front and rear support elements 28 and 29, respectively, of said tablet arm support 22. The tablet arm 23 is adapted to be normally disposed in a substantially horizontal position of use, as illustrated in FIG. 1. The tablet arm includes an enlarged front portion 26 adapted to support an article or writing materials, for example. An elongated arm rest 27 is connected to and extends rearwardly from the front portion 26.

The V-shaped tablet arm support 22 (FIG. 3) is disposed substantially within a vertical plane which is parallel with and outwardly of the vertical plane defined by the right pair of legs 13 and 14. The front and rear support elements 28 and 29, respectively, (FIG. 6) diverge upwardly and they are inclined forwardly and rearwardly, respectively, to the vertical. The lower ends of the elements 28 and 29 are rigidly, here integrally, connected by a central portion 31, which extends substantially horizontally and is disposed at an elevation approximately mid-way between the upper and lower ends ofthe chair legs.

The arm support 22 (FIG. 6) is rigidly connected to the legs I3 and 14 by means of weld brackets 32 and 32A. Particularly, a first X-shaped weld bracket 32 (FIGS. 6, 7 and 9) is disposed adjacent the point ofintersection of and between the front support element 28 and the front leg 13. The bracket 32 includes a first crossbar 33 which is disposed adjacent to and extends along the front support element 28. Said crossbar 33 has a concave outer surface, transversely thereof, which snugly embraces the cylindrical support element 28, but other cooperating surfaces could be provided.

the leg 13 by welds 34.

The bracket 32 includes another elongated crossbar 35 which is adjacent to and extends along front leg 13. The crossbar 35 is similar to crossbar 33 and is secured near the opposite ends thereof to the element 28 by welds 34.

An X-shaped bracket 32A (preferably a mirror image of bracket 32) is provided at the intersection of and between the rear leg 14 and the rear support element 29 for fixedly interconnecting same. The angle of intersection between the support elements 28 and 29 and the respective chair legs 13 and 14 are preferably identical so that the brackets 32 and 32A can be mirror images of each other. The crossbars 33, 35 and 33A, 35A of the X-shaped brackets are preferably integral so that they provide a strong and durable but flexible connector which can be easily fabricated and formed from sheet metal.

The upper ends of the support elements 28 and 29 are connected to and support hinge assemblies 36 and 37, which pivotally connect the tablet arm 23 to the V- shaped arm support 22. The hinge axes of the assemblies 36 and 37 are substantially disposed within the same horizontal plane and are coaxial. The assemblies 36 and 37 are preferably substantially identical to each other so that only the hinge assembly 36 need be described in detail.

The front hinge assembly 36 (FIGS. 2 and 8) includes a stationary hinge plate 38 rigidly secured, as by welding, to the upper end of the front support element 28. The hinge plate 38 is normally substantially horizontal and includes a flange 39 (FIG. 4) extending downwardly along approximately three edges thereof. The downwardly extending flange not only hides the weld seams between the element 28 and plate 38, but also imparts additional strength and rigidity to the hinge plate 38 and minimizes sharp edges or corners where they could be injurious. The hinge plate 38 is also provided with a conventional hinge knuckle 41 integral with an edge thereof.

The hinge assembly 36 includes a movable hinge plate 42 fixedly secured to the underside of the tablet arm 23 in a conventional manner, such as by means of screws 43, along the straight inner edge 48 thereof. The hinge plate 42 includes a pair of spaced and conventional hinge knuckles 44 integrally connected to the outer edge thereof. The hinge knuckles 44 are adapted to be axially aligned with and disposed on opposite axial ends of the hinge knuckle 41, so that a hinge pin 46 can be inserted through the aligned knuckles in a conventional manner for hingedly connecting the hinge plates 38 and 42.

The hinge assembly 36 is also provided with an elongated stop or abutment 47 fixedly secured to, and projecting downwardly from, the underside ofthe stationary hinge plate 38. The stop 47, which in the illustrated embodiment comprises a short rod welded to the hinge plate, is parallel with and laterallyspaced inwardly from the hinge pin 46. The stop 47 is positioned for engagement by the longitudinal edge 48 of the tablet arm 23 to arrest the pivotal movement thereof when it reaches the storage position substantially as illustrated in FIGS. 8 and 10. The stop 47 thus prevents the tablet arm from moving into suspended, substantially vertical position, but instead maintains the tablet arm in an inclined stacking or storage position wherein the tablet extends both downwardly and outwardly from the hinge axis thereof.

The hinge assembly 37 (FIGS. 2 and 4) has a fixed plate 38A with an integral knuckle 41A and a movable plate 42A with spaced integral knuckles 44A. A stop 47A is secured to the lower surface of plate 38A which has an integral flange 39A.

The chair is also preferably provided with ganging means for interlocking a plurality of said chairs in sideby-side relationship and in a row. The ganging means includes male and female ganging members, one being fixedly secured to one side of the chair and the other being secured to the opposite side thereof. In the illustrated embodiment, the male ganging member 51 (FIG. I) is disposed near the right pair of legs 13 and 14, and it is rigidly connected, as by welding, to the V-shaped tablet arm support 22 near the lower end thereof. The male member 51 is fabricated from metallic rod-like material arranged to form a horizontally elongated rectangle; Portions 50 of the member 51 are offset inwardly at the points of engagement between the member 51; and the elements 28 and 29 of the tablet arm support 22. This provision spaces the remainder of the member 51 away from the tablet arm support so that the female ganging member 52 can move downwardlypast the elements 28 and 29 during a stacking operation. The opposite substantially rectangular end portions 53 and 54 of the member 51 extend frontwardly and rearwardly beyond the legs 13 and 14, respectively.

The female gangingmember 52 (FIGS. 5 and 6) is fixedly connected to the left pair of legs 16 and 17. The female member 52' is also fabricated from metallic rodlike material arranged in ahorizontally elongated loop, said member 52 has opposite end portions 56 and 57 which extend frontwardly and rearwardly beyond the respective legs 16 and 17.

The end portions 56 and 57 on the'female ganging member 52 are both bent outwardly and are substantially perpendicular to the central portion of the member 52. These portions 56' and 57 converge upwardly so that they can overlapthe upper corners of the planarend portions 53 and 54 ofa male ganging member mounted upon a similar, adjacent chair, whereby the to chairs are releasably held in side-byside relationship.

The exact structural details of the ganging members 51 and 52, and the manner in which they coact, are explained in greater detail in copending application Ser. No. 79,732, filed.0ct. 12, I970, and entitled IM- PROVED GANGING AND STACKING 'CHAlR, which'application is assigned to the Assignee of this application.

While the ganging -members 51 and 52 may be secured to the legs 13, 14 and 16, 17, respectively, in any convenient manner, projection welding is preferred, because it' minimizes the heat required and/or generated to effect theweld.

As shown in FIG. 12, the hinge axes 61 and 62 of the hinge assemblies 36' and 37, respectively, are preferably at slight angles to the pivotal axis 63 of the arm 23 before said assemblies are attached to the arm. The amount of the angles may be relatively small, such as about 3 degrees. Thus, just before. the hinge plates 42 and 42A are secured to the arm 23, the support elements 28 and 29 are twisted around their lengthwise axes (28 counterclockwise and 29 clockwise) until the axes 61 and 62 are coincident with the axis 63. As a result, the torque applied to the elements 28 and 29 will react to prestress the hinge assemblies 36 and 37 whereby friction opposing pivotal movement of the arm 23 is increased to the point that the arm 23 will tend to remain in any position where it is placed between and including those shown in FIGS. 1 and 2. This arrangement improves the safety of the chair in that it avoids the accidental falling of the arm from a vertical, upright position, as shown at 23C in FIG. 3,

into either of thepositions at 23 and 23A.

OPERATION The normal position of use for the chair 10, built according to the present invention, is illustrated in FIG. 1, wherein the tablet arm is horizontally disposed above one edge portion of, and extending partially over, the seat so that the tablet arm is usable as a support surface. Further, if desired, a plurality of identical chairs, such as the identical chairs 10 and 10A illustrated in FIG. 3, can be ganged in side-by-side relationship to form a row of interconnected chairs. Particularly, the male ganging member 51 provided on the chair 10 is engaged by the female ganging member 52A provided on the chair 10A for interconnecting the chairs. The engagement of these ganging members is accomplished (FIGS. 6 and 7) by raising the chair 10A so that the female ganging member 52A is disposed directly above the male ganging member 51, after which chair 10A is lowered so that planar end portions of the male ganging member 51 extend into the sloped end portions formed on the female ganging member 52A. This interlocked relationship of the ganging members is accomplished .when both chairs are resting on the same planar surface.

Further, with the chairs in the ganged relationship illustrated in FIG. 3, each tablet arm 23 can be individually swung around its hinge axis from its use position of FIG. 1 into its storage position of FIG. 2 to facilitate movement ofa person into or out of the chair. As is clearly illustrated in Figure, movement of the tablet arm from its use position to its storage position involves swinging'the tablet 'arm about its hinge axis through an angle substantially in excess of When it is desired to stack the chairs one upon another, the tablet arm 23 of each'chair is first moved into the storage position illustrated in FIG. 2, wherein the tablet arm extends downwardly and outwardly from its hinge axis. The hinged movement of the tablet arm is 'limited by engagement between the hinge stop 47 and the longitudinal edge 48 of the tablet arm.

With the tablet arms in the storage position, the chairs can be stacked one on top of another substantially as illustrated in FIGS. 10 and 11. The downward divergence of the front and rear legs, whereby the legs of an upper chair are disposed above and ride on the legs of a lower chair, prevents said legs from interfering with the vertical stacking. The laterally offset location and the V-shaped configuration of the tablet arm supports 22 prevents their interference with the stacking operation. The storage position of the tablet arms is such that they are disposed one above another in the stacked positions, as illustrated inFIG. 10. The vertical nesting of the V-shaped tablet supports is made possible by the fact that the hinge pin 46 is laterally and outwardly offset from the support elements 28 and 29. Thus, when the tablet arm 23 is in the storage position, the tablet support 22B of the chair lB, directly above chair 10, can pass vertically downwardly between the pair of stationary hinge plates 38 and 38A on the lower chair 10.

When the chairs are in the stacked position, the weight of an upper chair is preferably transferred to the next lower chair due to bearing engagement between the legs of the two stacked chairs. However, the tablet arm support 22 may also be engaged by the support 228 when the chairs are in stacked positions.

While the chairs illustrated in the drawings are all provided with a pivotally movable tablet arm mounted on the side of the chair suitable for right-handed persons, it will be readily apparent that the present invention is also adaptable for so-called left-handed chairs, that is, chairs having the swingable tablet mounted on the opposite side of the chair.

The bracket 32 (FIGS. 7 and 9)'is constructed, and the bars 33 and 35 thereof are attached to the element 28 and leg l3, respectively, so that adverse effects from welds under stress at least minimized. That is, for example, the bar 33 is welded to the element 28 at two points substantially spaced, such as three or four inches, and each weld can be relatively small, by comparison with a conventional weld which would be required directly between the leg 13 and element 28, if the bracket 32 were not used. The small welds are completely adequate because both the bar 33 and the portion of the element 28 between the welds can flex under stress, and this greatly reduces the likelihood ofa break at the weld when a stress is applied to the element 28 or leg 13.

Since the welds are small and produced by a fast acting electrical process, annealing is minimized and restricted to the immediate location of the weld. Thus, there is no extensive, heat affected zone which has a lower yield strength and, hence, a lower resistance to failure under stress.

The bracket 32 obviously strengthens the adjacent portions of the leg 13 and element 28, but is does not create stress concentrations due to abrupt, large changes in cross-sectional area. A stress applied to the leg 13, for example, is distributed along almost the full length of the bar 35 in a manner very nearly corresponding to such distribution if the leg was unattached to the bracket 32 or the element 28.

The brackets 32 and 32A also serve as accurate spacers between the legs and arm support 22 to facilitate stacking or nesting of plural chairs [0.

The method of pre-stressing the hinges 36 and 37 (FIG. 12) is accomplished by applying a torque or torsional deflection to the elements 28 and 29 prior to attachment of their hinges to the arm rest 23. The restoring forces within the elements 28 and 29 impose a distortion upon their hinges whereby frictional resistance to the movement of the arm rest can be substantially increased in a predetermined manner.

Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A stackable tablet arm chair comprising:

seat means and front and rear pairs of legs rigidly secured to said seat means, said front legs diverging downwardly with respect to said rear legs, said rear legs substantially defining a first plane sloping downwardly and rearwardly relative to said seat means, and said front legs substantially defining a second plane sloping downwardly and frontwardly relative to said seat means;

tablet arm support means disposed adjacent one side of said seat means and rigidly secured to a pair of said legs, said am support means having a pair of spaced upwardly extending and substantially straight support elements located on said one side of said seat means, said support elements diverging upwardly and extending substantially the same distance from a third plane defined by the lower ends of said front and rear legs;

tablet arm means and hinge means connecting said arm means along one edge thereof to the upper ends of said support elements for pivotal movement of said tablet arm means through an angle in excess of around a hinge axis substantially parallel with said third plane, said hinge means permitting pivotal movement of said tablet arm means between a first position wherein said tablet arm means is directly above a part of said seat means and substantially parallel with said third plane and a second position wherein said tablet arm means is on the opposite'side of said hinge axis from said first position and slopes downwardly from said hinge axis.

2. A chair according to claim 1, wherein said hinge means comprises a pair of substantially planer first hinge plates rigidly secured to and extending side-- wardly from the upper ends of said support elements, a pair of substantially planer second hinge plates rigidly secured to said tablet arm means, a pair of hinge pins pivotally connecting said first hinge plates to said second hinge plates, and stop means on the lower sides of said first hinge plates and engageable by said edge of said tablet arm means when said tablet arm means is in said second position.

3. A chair according to claim 1, including first ganging means rigidly connected to the legs on one side of said seat means and second ganging means rigidly connected to the legs on the other side of said seat means, a said first ganging means on one said chair being engageable with a said second means on another said chair when the lower ends of the legs of both said chairs are disposed substantially within said third plane whereby said chairs are held against relative movement in a direction substantially parallel with said third plane.

4. In a stackable chair having legs and an elongated arm rest support element transverse of and adjacent to one of said legs, and means for fixedly and rigidly interconnecting said element to said one leg, the improvement wherein said last-mentioned means comprises:

X-shaped bracket means having a pair of interconnected cross-bars, one crossbar having a surface on one side thereof embracing said element near said one leg and the other crossbar having a surface on the other side thereof embracing said one leg near said element; and

weld means fixedly and rigidly securing said crossbars to said leg and said element when said surfaces are adjacent thereto, said weld means being near the opposite ends of said crossbars and spaced from the point of intersection of said leg and said element.

5. interconnecting means according to claim 7 wherein said leg and said element are substantially cylindrical and hollow adjacent said interconnection thereof; and

wherein said surfaces are concave transversely of their lengthwise extents.

6. In a chair having a pivotable, tablet arm rest and frame means including a seat, an arm rest support comprising:

a pair of spaced, substantially upright elements secured to and extending upwardly from said frame means; and

a pair of hinge means connecting said arm rest to said elements for pivotal movement around an axis spaced from said seat;

at least one of said elements being resiliently flexible and having a torque applied thereto prior to attachment of said pair of hinge means to said arm rest, said one element thereby having a torsional stress when both elements are attached to said arm rest, whereby the friction in the hinge means attached to said one element is increased to resist pivotal movement of said arm rest.

7. An arm rest support according to claim 6 wherein the other element is resiliently flexible and has a torque applied thereto prior to attachment thereof by the other hinge means to said arm rest.

8. A chair according to claim 3, wherein said first hinge plates are fixedly secured directly to the upper ends of said support elements and are disposed substantially within a horizontal plane, and said hinge axis being horizontally sidewardly displaced from the upper ends of said support elements in a direction away from said seat means. 

1. A stackable tablet arm chair comprising: seat means and front and rear pairs of legs rigidly secured to said seat means, said front legs diverging downwardly with respect to said rear legs, said rear legs substantially defining a first plane sloping downwardly and rearwardly relative to said seat means, and said front legs substantially defining a second plane sloping downwardly and frontwardly relative to said seat means; tablet arm support means disposed adjacent one side of said seat means and rigidly secured to a pair of said legs, said arm support means having a pair of spaced upwardly extending and substantially straight support elements located on said one side of said seat means, said support elements diverging upwardly and extending substantially the same distance from a third plane defined by the lower ends of said front and rear legs; tablet arm means and hinge means connecting said arm means along one edge thereof to the upper ends of said support elements for pivotal movement of said tablet arm means through an angle in excess of 180* around a hinge axis substantially parallel with said third plane, said hinge means permitting pivotal movement of said tablet arm means between a first position wherein said tablet arm means is directly above a part of said seat means and substantially parallel with said third plane and a second position wherein said tablet arm means is on the opposite side of said hinge axis from said first position and slopes downwardly from said hinge axis.
 2. A chair according to claim 1, wherein said hinge means comprises a pair of substantially planer first hinge plates rigidly secured to and extending sidewardly from the upper ends of said support elements, a pair of substantially planer second hinge plates rigidly secured to said tablet arm means, a pair of hinge pins pivotally connecting said first hinge plates to said second hinge plates, and stop means on the lower sides of said first hinge plates and engageable by said edge of said tablet arm means when said tablet arm means is in said second position.
 3. A chair according to claim 1, including first ganging means rigidly connected to the legs on one side of said seat means and second ganging means rigidly connected to the legs on the other side of said seat means, a said first ganging means on one said chair being engageable with a said second means on another said chair when the lower ends of the legs of both said chairs are disposed substantially within said third plane whereby said chairs are held against relative movement in a direction substantially parallel with said third plane.
 4. In a stackable chair having legs and an elongated arm rest support element transverse of and adjacent to one of said legs, and means for fixedly and rigidly interconnecting said element to said one leg, the improvement wherein said last-mentioned means comprises: X-shaped bracket means having a pair of interconnected cross-bars, one crossbar having a surface on one side thereof embracing said element near said one leg and the other crossbar having a surface on the other side thereof embracing said one leg near said element; and weld means fixedly and rigidly securing said crossbars to said leg and said element when said surfaces are adjacent thereto, said weld means being near the opposite ends of said crossbars and spaced from the point of intersection of said leg and said element.
 5. Interconnecting means according to claim 7 wherein said leg and said element are substantially cylindrical and hollow adjacent said interconnection thereof; and wherein said surfaces are concave transversely of their lengthwise extents.
 6. In a chair having a pivotabLe, tablet arm rest and frame means including a seat, an arm rest support comprising: a pair of spaced, substantially upright elements secured to and extending upwardly from said frame means; and a pair of hinge means connecting said arm rest to said elements for pivotal movement around an axis spaced from said seat; at least one of said elements being resiliently flexible and having a torque applied thereto prior to attachment of said pair of hinge means to said arm rest, said one element thereby having a torsional stress when both elements are attached to said arm rest, whereby the friction in the hinge means attached to said one element is increased to resist pivotal movement of said arm rest.
 7. An arm rest support according to claim 6 wherein the other element is resiliently flexible and has a torque applied thereto prior to attachment thereof by the other hinge means to said arm rest.
 8. A chair according to claim 3, wherein said first hinge plates are fixedly secured directly to the upper ends of said support elements and are disposed substantially within a horizontal plane, and said hinge axis being horizontally sidewardly displaced from the upper ends of said support elements in a direction away from said seat means. 